Britain’s role in exporting arms and providing military advisers for the Saudi Arabian-led bombing campaign in Yemen is under scrutiny following a UN report revealing widespread attacks on civilian targets.

The report, which was obtained by The Guardian and has not yet been published, found that Saudi airstrikes are breaching international law by hitting civilian targets, including refugee camps, civilian weddings, vehicles, medical facilities and schools.

The UN panel of experts on Yemen used satellite imagery to look at areas before and after bombings, which also targeted an Oxfam warehouse storing equipment for a water project funded by the EU.

Speaking at Prime Minister’s Questions (PMQs) on Wednesday, David Cameron defended arms sales to Saudi Arabia insisting the UK has the “strictest” arms controls of any country in the world. It is not known whether Cameron was aware of the UN report at the time.

Britain has denied its military advisers are helping Saudi Arabia in “an operational role,” insisting they are instead helping to “ensure continued compliance with international humanitarian law.”

The UK sold over £1 billion worth of missiles, rockets and bombs to Saudi Arabia last summer, an extraordinary increase in sales which prompted human rights organizations to accuse the British government of war profiteering.

The damning UN report found widespread attacks on civilians and infrastructure.

“The panel documented that the coalition had conducted airstrikes targeting civilians and civilian objects, in violation of international humanitarian law, including camps for internally-displaced persons and refugees; civilian gatherings, including weddings; civilian vehicles, including buses; civilian residential areas; medical facilities; schools; mosques; markets, factories and food storage warehouses; and other essential civilian infrastructure, such as the airport in Sana’a, the port in Hudaydah and domestic transit routes,” the report says.

Speaking last week, Cameron defended Britain’s arms trade with the Saudis, arguing the UK has the most robust export controls on weapons in the world.

“In terms of our arms exports I think we have some of the most stringent controls anywhere in the world and I’ll always make sure they’re properly operated,” he told BBC Radio 4’s Today program.

“We’re trying to do everything we can to make sure that the work done by Saudi Arabia is properly targeted and it’s right that we should do that. We’re working with them and others on behalf of the legitimate government on Yemen.”